Phenomenology and physical origin of shear-localization and shear-banding in complex fluids

TL;DR

This paper reviews the phenomenology and physical origins of shear-localization and shear-banding across various complex fluids, highlighting their common physical mechanisms and the conditions under which they occur.

Contribution

It provides a comparative analysis of shear-banding phenomena in different complex fluids and proposes a unified physical origin based on competing phenomena.

Findings

Shear-banding involves a gradual viscosity bifurcation in adjoining regions.

Shear-banding is driven by competing physical phenomena like destructuration and aging.

Shear-banding occurs in various complex fluids with a common physical origin.

Abstract

We review and compare the phenomenological aspects and physical origin of shear-localization and shear-banding in various material types, namely emulsions, suspensions, colloids, granular materials and micellar systems. It appears that shear-banding, which must be distinguished from the simple effect of coexisting static-flowing regions in yield stress fluids, occurs in the form of a progressive evolution of the local viscosity towards two significantly different values in two adjoining regions of the fluids in which the stress takes slightly different values. This suggests that from a global point of view shear-banding in these systems has a common physical origin: two physical phenomena (for example, in colloids, destructuration due to flow and restructuration due to aging) are in competition and, depending on the flow conditions, one of them becomes dominant and makes the system evolve in a specific direction.